Tagged Questions

Energy is the conserved quantity associated to time-translation invariance and represents the work a system is capable of doing. Use this tag for questions about energy, and consider adding [tag:energy-conservation] if it is specifically about its conservation.

I'm a bit in doubt about whether the concept of potential energy has any correspondence to the real world.
Real world entities can't change their magnitude in an instant, nor without being affected ...

From Wikipedia: "Under the special theory of relativity, a particle (that has rest mass) with subluminal velocity needs infinite energy to accelerate to the speed of light, to accelerate beyond the ...

I am currently doing an experiment where I am burning methanol to test for the heat of combustion. To test this, I am heating 100g of water and raising it by 20 degrees Celsius before extinguishing ...

A neutron star remnant consists mostly of neutron degenerate matter. If you happened to suddenly have 1 kg of it in your lap without the pressure necessary to keep it degenerate, I suppose it would ...

We all know that energy is never lost, but it transforms into another form.
Doesn't that mean that energy is not unlimited? I mean, why is it that way if it was infinite?
However, if energy is spread ...

What is more fuel efficient: Two identical cars running at 50mph or one being tied to the other and only the first dragging both at 50mph? Or what requires less fuel: Two cars to start from stop and ...

Einstein is regarded to be one of the most brilliant minds partly for the equation E = mc^2. In addition to quantifying the relationship between the two, he was the first to introduce the idea that ...

The initial kinetic energy of an object moving on a horizontal surface is K.Friction between the object and the surface causes the velocity of the object to decrease uniformly to zero in time,t.How ...

The initial kinetic energy of an object moving on a horizontal surface is K.Friction between the object and the surface causes the velocity of the object to decrease uniformly to zero in time,t.How do ...

I have searched for equations regarding craters and I came across two of them. The first one is from this NOAO website in the level two section. There, it says that,
$$
D^3\propto E
$$
where $E$ is ...

At the point horizontally across and equidistant from the centers of the two charges (also oriented horizontally), what is the electric potential? At that point, the electric field of the first charge ...

I am aware that in order for energy to be conserved the reference frame that you are using must be inertial. However, consider the situation where you are using the reference frame of the earth and ...

I know that helium and CO2 are used as fast reactor coolants, but how about other inert gasses with low neutron absorption, like argon, why do I see no papers on that?
Oh and bonus question. Why is ...

whilst exploring the second law of thermodynamics, I have come across the terms enthalpy and entropy. I have seen these terms before and thought that I knew what they meant, but I have seen them used ...

Objects possess potential and kinetic energies. The potential energy depends on the position of the object, while the kinetic energy is dependent on its velocity.
My question: are there other types ...

One of the better known physics demonstrations for standing wave resonance is the singing rod . By holding the rod exactly in the middle the demonstrator constrains the first mode of excitation - the ...

I still don't get what it means for atomic energy levels to be continuous or quantitized (incontinuous). Clearing this up will really help me. Also, can anyone tell me why energy levels in solids are ...

Magnetic fields can't do work. However, we use the following equation to describe the energy density of a magnetic field.
$u = \frac{B^2}{2\mu_0}$
The term energy density suggests that the magnetic ...

It's common knowledge that due to relativistic effects, accelerating from 0.8c to 0.9c takes a lot more energy than accelerating from 0.1c to 0.2c.
However, what's the case with deceleration? Does it ...

It's the same body made by the rider and the bike moving at the same speed. So, even though braking on the front/back alters the normal forces on the opposite wheels thus creating more friction with ...